Editing IMSA (section)

===Purchase by NASCAR and reunification===
{{Further|IMSA SportsCar Championship}}
[[File:2014 Rolex 24 Hours of Daytona (12178633616).jpg|thumb|[[2014 24 Hours of Daytona]], first race of reunified IMSA SportsCar Championship]]
In 2012, Don Panoz sold the Braselton, Georgia-based ALMS to [[Grand-Am Road Racing]], in turn owned directly by [[NASCAR]] and helped organize a merger between the ALMS and the [[Rolex Sports Car Series]]. In 2013 the unified series was announced as the Tudor United SportsCar Championship (now [[IMSA SportsCar Championship]]). The announcement also confirmed that IMSA will manage and sanction the new series, operating as a wholly owned subsidiary of NASCAR.

On September 19, 2019, Scott Atherton announced retirement from his position as the President of the International Motor Sports Association at the end of 2019. He had held that role since the merger of IMSA's [[American Le Mans Series]] with the Grand-Am [[Rolex Sports Car Series]] in 2014.<ref name="Atherton">{{cite web|url=https://racer.com/2019/09/19/atherton-to-leave-imsa-after-2019-season/|title=Atherton to leave IMSA after 2019 season|last=Pruett|first=Marshall|date=September 19, 2019|work=racer.com|publisher=Racer Media & Marketing, Inc|access-date=September 20, 2019}}</ref> One month following that announcement, then-director of [[Mazda]]'s motorsports program in North America, John Doonan, was confirmed to be Atherton's replacement.<ref name="DoonanPresident">{{cite web|url=https://racer.com/2019/10/15/doonan-named-new-imsa-president/|title=Doonan named new IMSA president|last=Pruett|first=Marshall|date=October 15, 2019|work=racer.com|publisher=Racer Media & Marketing Inc.|access-date=October 30, 2019}}</ref>  Ed Bennett, longtime NASCAR executive, was also President and CEO of Grand-Am Road Racing from August 2011 to December 2013 during the merger period and has continued as CEO of the modern era IMSA since January 2014.<ref name=":1" />

At the 2021 Daytona 24 Hours, IMSA and the ACO announced the historic alignment of the technical regulations for sportscar racing, which was further detailed in June of that year, which brought about the convergence of all sportscar regulations between the FIA, IMSA and the ACO.<ref>{{cite web |date=18 June 2013 |title=IMSA Senior Leadership Team Organizational Structure Finalized |url=https://www.automobilsport.com/race-categories--24,112459,IMSA-Senior-Leadership-Team-Organizational-Structure-Finalized,news.htm|archive-url=https://web.archive.org/web/20230527152127/https://www.automobilsport.com/race-categories--24,112459,IMSA-Senior-Leadership-Team-Organizational-Structure-Finalized,news.htm|url-status=usurped|archive-date=May 27, 2023}}</ref>

In January 2022, IMSA bought [[Historic Sportscar Racing]], whose events include the Classic 24 Hours of Daytona, the Classic 12 Hours of Sebring  and the [[Rolex Monterey Motorsports Reunion]].<ref name=":1">{{Cite web|url=https://www.imsa.com/news/2022/01/27/imsa-acquires-historic-sportscar-racing/|title=IMSA Acquires Historic Sportscar Racing &#124; IMSA}}</ref>